Lab Insights

Cell Death Insights with Celloger®: From Mechanisms to Real-Time Cytotoxicity Monitoring

Cell death is a natural, tightly regulated process that removes damaged, infected, or unnecessary cells and helps maintain tissue homeostasis.In our previous articles, we covered how cells grow and divide—starting with the cell cycle [article link] and then moving to mitosis and cytokinesis [article link], where cells separate their genetic material and complete division. When these steps fail, cells can undergo regulated cell death to prevent abnormal cells from persisting.In this article, we provide a clear overview of major cell death pathways and show how live-cell imaging can track cytotoxicity in real time, capturing morphological changes as well as the timing and extent of cell death. Table of Contents1. Overview of Cell Death2. Types of Regulated Cell Death3. Methods for Measuring Cytotoxicity4. Case study: Live-Cell Imaging of Nocodazole-Induced Cytotoxicity 1. Overview of Cell DeathCell death can be broadly classified into two major forms: accidental cell death (ACD) and regulated cell death (RCD). These two forms differ in how they are triggered, how rapidly they progress, and how much cellular control is involved.(1) Accidental Cell Death (ACD)ACD is an uncontrolled process that occurs when cells are exposed to sudden and severe physical, chemical, or mechanical stress. Because the damage is sudden and overwhelming, ACD generally occurs rapidly and does not rely on regulated signaling pathways that control its timing or execution.(2) Regulated Cell Death (RCD)RCD is a controlled process in which cells are directed to die through specific molecular pathways. These pathways determine when and how cell death occurs and can be modulated by intracellular or extracellular signals. Unlike ACD, RCD enables damaged or unwanted cells to be eliminated in a more selective and controlled manner, and it can be influenced by genetic or pharmacological interventions. 2. Regulated Cell Death TypesRegulated cell death (RCD) comprises several distinct pathways, each defined by characteristic molecular and morphological features. Among these, five major types are commonly discussed in cell biology.(1) Apoptosis: A caspase-driven, programmed cell death marked by cell shrinkage, membrane blebbing, and apoptotic body formation. Common readouts include caspase-3/7 activation and PARP cleavage.(2) Necroptosis: A regulated, lytic cell death pathway often triggered when apoptosis is blocked, characterized by cell swelling and membrane rupture. A key marker is MLKL activation.(3) Pyroptosis: An inflammasome-related, inflammatory cell death caused by gasdermin pore formation, leading to rapid swelling and membrane rupture. Typical readouts include gasdermin cleavage and IL-1β release.(4) Ferroptosis: An iron-dependent cell death driven by lipid peroxidation and lipid ROS accumulation, sometimes accompanied by mitochondrial shrinkage. It is commonly monitored using lipid peroxidation/ROS assays and ferroptosis modulators.(5) Autophagy-dependent cell death: A regulated cell death that requires autophagy machinery and may show increased autophagic vacuoles. LC3-II and p62 changes can support interpretation, but should be considered alongside autophagic flux.These regulated cell death pathways differ in their triggers, morphological changes, and typical markers, as summarized in the table below. While these pathways have distinct features, they can overlap in practice. Accurate assessment of cell death therefore requires appropriate measurement methods, as discussed in the following section. 3. Methods for Measuring Cell Death & CytotoxicityAccurately assessing cell death is essential in research areas such as drug testing, toxicity studies, and cell biology. Rather than relying on a single indicator, cytotoxicity is evaluated by monitoring cellular changes associated with loss of viability and cell death. Based on the type of change being measured, cytotoxicity assays can be broadly grouped into three main categories.(1) Assessing membrane integrity : One of the most direct ways to identify dead or dying cells is to evaluate plasma membrane integrity. In healthy cells, the plasma membrane remains intact and prevents membrane-impermeant dyes from entering the cell. When membrane integrity is compromised, fluorescent DNA-binding dyes enter the membrane and bind to DNA, producing a detectable fluorescent signal indicative of cell death. PI, EthD-1, and CellTox™ Green dye are commonly used to detect loss of membrane integrity. The representative image below shows HEK293 (GFP-tagged) cells stained with EthD-1. ▶ Watch the time-lapse video on YouTube (2) Detecting enzymatic activity : Another approach to evaluating cytotoxicity is to use enzyme activity–based readouts. Some dyes report cell viability by fluorescing only when intracellular enzymes remain active, with signals decreasing as cells lose viability. Other enzyme-based probes detect protease activity (e.g., caspases or granzymes) and become fluorescent when these pathways are activated, enabling early detection of cells undergoing cell death. Common dyes for enzymatic activity assays include Calcein-AM, CellTracker™ Green CMFDA, and CellEvent™ Caspase-3/7 detection dye. The example below shows HeLa cells stained with CellEvent™ Caspase-3/7 detection dye. ▶ Watch the time-lapse video on YouTube (3) Measuring metabolic activity : Cytotoxicity can also be assessed by measuring metabolic activity, which reflects overall cell function and viability. Metabolically active cells maintain ATP levels or convert substrates into detectable products, whereas decreased metabolic signals indicate reduced viability and declining cell health. Common dyes used to assess metabolic activity include JC-10 and BioTracker ATP-red live cell dye. The example below shows HeLa cells stained with JC-10 under control and CCCP-treated conditions. ▶ Read the application note on mitochondrial membrane potential analysisChoosing the right assay is essential because each method captures a different aspect of cytotoxicity—such as cell death, cell viability, or overall cell health. Using an appropriate method ensures accurate interpretation of cellular responses. To illustrate how these approaches are applied in practice, the following section presents live-cell imaging–based examples of drug-induced cell death. 4. Observation Example : Nocodazole-induced Cell DeathLive-cell imaging enables continuous monitoring of cellular responses to drug-induced cytotoxicity, capturing both morphological changes and cell death signals within the same experiment. This approach allows cytotoxic effects to be tracked over time rather than relying on a single endpoint measurement. The table below summarizes the observation conditions used to monitor nocodazole-induced cytotoxicity using live-cell imaging. Time-lapse imaging revealed clear, concentration- and time-dependent cytotoxic responses during nocodazole treatment. Brightfield images showed a progressive decline in cell confluency, while fluorescence imaging displayed increasing dead-cell signals, consistent with ongoing cell death.To explore these changes in more detail, the corresponding Celloger® Mini Plus time-lapse video is available at the link below. ▶ Watch the time-lapse video on Youtube Following these visual observations, the cytotoxic effects of nocodazole were further evaluated using quantitative analysis. Cell death was quantified over time using Celloger analysis software by calculating the ratio of fluorescent signal coverage (dead cells) to brightfield confluency (total cells). The results show a clear concentration- and time-dependent increase in cytotoxicity. These quantitative findings align with time-lapse observations, showing reduced cell confluency and increased fluorescent dead cell signals over time.By integrating real-time imaging with fluorescence-based quantification, this approach enables reliable assessment of the timing and progression of drug-induced cell death.▶ Learn more about Celloger® Mini Plus: In this article, we explored how cell death pathways can be triggered when normal cellular processes fail. We also showed how these dynamic changes can be observed over time using live-cell imaging. Rather than relying on static endpoint measurements, this approach enables continuous monitoring of cellular responses under experimental conditions. To learn more about live-cell imaging systems and their applications in cell research, visit the Curiosis website.

2026-07-24
Inside Curiosis Bio Research Team: Defining Scientific Standards for Reliable Research

As automated laboratory systems advance, ensuring that experimental data remain consistent and reproducible is increasingly critical. In real research environments, performance is defined not only by specifications, but by how reliably results can be maintained across different users, instruments, and conditions. At Curiosis, the Bio Team evaluates whether equipment performs consistently in practice, defines measurable evaluation criteria, and verifies that data generated in the lab can be trusted in real experimental workflows. We spoke with Seung‑jung Song, Director of the Research Institute, about how this validation process supports reliable research. Q1. Could you introduce yourself and your role at Curiosis?Dr. Song: I am Seung-jung Song, Director of the Bio Team at the Curiosis Affiliated Research Institute. I lead the Bio Team and am responsible for defining scientific and experimental standards, validating application data, and verifying equipment performance across our product lines.Our team participates throughout the product lifecycle—from planning and development to production and post-launch—ensuring reproducibility and consistency in real research environments.Q2. What is the role of the Bio Team at Curiosis?Dr. Song: The Bio Team defines scientific and experimental standards and checks whether our products perform reliably in real research environments.In the planning stage, we begin by setting performance standards and defining evaluation criteria based on scientific requirements. During development, we verify equipment performance and validate application data through repeated testing. In production, we look closely at consistency and reproducibility across instruments and users. Even after launch, we continue to monitor performance within real laboratory workflows to ensure scientific reliability. Q3. What criteria do you use to evaluate equipment performance?Dr. Song: We focus on data quality and real applicability within actual research workflows.When evaluating equipment, we examine whether repeated measurements produce consistent results and compare performance against existing standard methods.We also assess variability across different users and instruments, since this directly affects scientific reliability. For the Bio Team, evaluation is not just a technical test, but a process of verifying scientific meaning and real user experience. Q4. Could you share a case where Curiosis equipment made a meaningful difference in real research settings?Dr. Song: The Celloger® live-cell imaging system is particularly valuable in research that requires quantitative analysis of cellular responses over time.For example, in cytotoxicity studies, researchers typically quantify increases in fluorescence signals from dead cells over time, often by calculating fluorescence intensity across the entire field of view.When cell numbers change over time or when cells occupy only part of the image, this method may not fully reflect actual cellular responses. Because background regions are included in the calculation, differences in cell density and time‑dependent changes in cell number can dilute the final quantitative results. To address this, Celloger® measures total cell area using bright-field images and then recalculates the proportion of fluorescently labeled dead cells specifically within the cell-occupied region. By quantifying only where cells are actually present, the system ensures that variations in cell density and time-dependent changes in cell number are accurately reflected in the data. As a result, quantitative outputs align more closely with visually observed patterns of cell death, enabling researchers to interpret cytotoxicity data with greater accuracy and confidence. Q5. In which research fields or applications is Celloger® particularly effective?Dr. Song: As discussed earlier, Celloger® shows particular strength in research where time-dependent changes are central to data interpretation.Rather than relying on end-point measurements, the system enables continuous monitoring of cellular responses inside the incubator.Researchers can observe when changes begin and how they progress over time, allowing them to follow the dynamic progression of cellular behavior under stable culture conditions.Because these temporal changes can be directly tracked and reviewed, experimental results can be interpreted in a more objective and verifiable way. For this reason, Celloger® is especially valuable in studies involving cell proliferation, cell migration, morphological changes, drug response, and the progression of cell death — research areas where understanding how cellular responses evolve over time is essential. 🔗 Discover Celloger® Live-Cell Imaging Systems → View Product Lineup🎥 Watch Celloger® Application Video → View on YouTube Q6. How does the Bio Team approach collaboration with the development team?Dr. Song: In the collaboration process, the Bio Team interprets equipment functions from the researcher’s perspective and connects them to technical implementation and user experience.We share experience-based information with the development team — such as the objectives and conditions under which experiments are conducted, the variables and decision criteria required in the interpretation process, and the stages at which inconvenience may arise.After development, during the testing phase, we verify whether the workflow and UI design operate in accordance with experimenters’ behavior and interpretation patterns, and we suggest improvements when necessary.Ultimately, collaboration with the development team is not simply about checking functionality, but about providing feedback based on researchers’ behavior and interpretation approaches so that development direction remains user-centered. Q7. As Curiosis enters a new phase of growth, how is the Bio Team’s role evolving?Dr. Song: As Curiosis enters a new phase of growth, the Bio Team’s role is expanding from internal performance validation to externally demonstrated scientific credibility.Prior to listing, our primary focus was on developing equipment and quantitatively validating performance against defined internal standards. However, as a listed company, product performance must go beyond internal verification. It must meet the expectations of the market, the academic community, and global users in terms of evidence and reproducibility.For this reason, the Bio Team is placing greater emphasis on generating evidence-based materials — such as research papers, white papers, and application notes — that clearly connect the intended use of the equipment with its scientific value.At the same time, performance indicators that we have continuously managed internally are being further refined into objective evaluation criteria that can be externally recognized. Our goal is to build a system where reproducibility can be demonstrated with clear metrics, regardless of the user or research environment.Ultimately, the Bio Team’s role is expanding toward providing evidence-based communication that explain not only how the technology works, but why it matters in real research contexts. Q8. Given this expanded role, what competencies or mindset are most important for the Bio Team today?Dr. Song: Two competencies are especially important for the Bio Team today — the ability to translate between experimental and development languages, and the ability to prioritize and align perspectives.First, the Bio Team acts as a bridge between researchers and developers. Researchers focus on the biological meaning of results, while developers consider the technical structures and parameters required to produce them. Our role is to translate experimental observations into clearly defined technical criteria — explaining why a feature is needed, when it should be used, and how it should function. Second, prioritization and coordination are essential. Since not every request can be implemented immediately, we assess user impact and propose realistic directions based on usability and research relevance.The Bio Team connects research objectives, user experience, and technical implementation, helping ensure that the product becomes a trusted tool in real research environments. Q9. What values guide you most in the research process?Dr. Song: The values I consider most important in research are deep understanding of phenomena and the ability to communicate that understanding clearly.Research is not only about generating data, but about understanding why results occur and making that reasoning transparent so others can interpret them in the same way. Only then can research lead to conclusions that are reliable and trustworthy. Q10. Lastly, is there any message you would like to convey to researchers or partners who use Curiosis’ technology?Dr. Song: Curiosis’ technology was designed to help researchers observe cellular phenomena more clearly and in greater depth.In research, small differences can lead to meaningful changes, and unexpected variations can open new directions of inquiry. We have focused on building tools that help capture those moments with greater precision.We hope our systems go beyond simply recording results and instead support researchers in understanding the broader flow of their studies. By enabling clearer interpretation of time-dependent and condition-specific patterns, our technology aims to help uncover meaningful insights within data. We hope this contributes to deeper scientific discovery and, in turn, supports the development of stronger evidence and the advancement of scientific inquiry. We sincerely thank Seung‑jung Song for sharing valuable time and thoughtful insights. Her perspective offered a deeper understanding of how Curiosis approaches scientific validation and meaningful innovation in lab automation.At Curiosis, we remain committed to building technologies that support reliable, reproducible, and well‑interpreted research, and we will continue developing systems that help researchers better understand and advance their work.🔗 Explore opportunities to grow with us → Careers at Curiosis

2026-04-15
Mitosis and Cytokinesis: From Theory to Live-Cell Imaging

IntroductionIn our previous article on the cell cycle(see the full article 👉🏻 Click to view), we outlined how cells move through G1, S, G2, and M. This follow-up focuses on the most visibly dynamic steps: Mitosis and Cytokinesis. Mitosis segregates duplicated chromosomes into two nuclei, while cytokinesis divides the cytoplasm and cleaves the plasma membrane to produce two daughter cells. These steps are central to growth, tissue repair, and genomic stability. When these processes fail, they can contribute to disease, including cancer. For the same reason, understanding these processes is crucial for researchers developing anti-mitotic or cytokinesis-modulators. In this post, we walk through each process step by step, explain how control mechanisms and checkpoints coordinate these steps, and share live-cell imaging results of mitotic errors and cytokinesis defects. Table of Contents1. Mitosis- Process and Regulation- Observation Example2. Cytokinesis- Process and Regulation- Observation Example 1. MitosisMitosis is the stage that separates duplicated chromosomes into two nuclei. It prepares the cell for cytokinesis, which divides the cytoplasm and completes cell division. Process and Regulation Mitosis proceeds through five distinct stages—prophase, prometaphase, metaphase, anaphase, and telophase. ProphaseChromosomes condense while centrosomes separate, initiating the formation of the mitotic spindle. PrometaphaseThe nuclear envelope breaks down, and spindle microtubules attach to chromosomes at kinetochores**Kinetochore: the protein complex at the centromere where spindle microtubules attach MetaphaseAll chromosomes line up in the middle of the cell so they are ready to be pulled to opposite sides. AnaphaseSister chromatids separate and move to opposite sides as the spindle pulls on them. TelophaseNew nuclear envelops form around each set of chromosomes, the chromosome decondense, and the cell begins cytokinesis. The spindle assembly checkpoint (SAC) ensures accuracy by monitoring kinetochore–microtubule attachment and tension during prometaphase and metaphase. It keeps the cell at metaphase until all chromosomes are properly attached; only then does anaphase begin. If attachment errors persist, the cell stays arrested and may trigger apoptosis. For the full checkpoint map, see the previous article 👉🏻 Click to view This checkpoint can be activated with small molecules such as nocodazole, which disrupt microtubules and arrest cells in prometaphase to study cell-cycle regulation. Observation Example - Mitosis Arrest Building on the overview above, the following example shows how disrupting spindle attachment alters mitotic progression. Control HeLa cells expressing GFP-H2B condense chromosomes, align them at the metaphase plate, and then separate into two nuclei in sequence. Nocodazole-treated cells fail to form proper attachments to spindle fibers, so they remain arrested in metaphase. Over time, some of these cells lose adhesion or undergo apoptosis. 👉🏻 For detailed information, see the Application Notes Once chromosome are segregated, cytokinesis partitions the cytoplasm and completes cell division. 2.CytokinesisCytokinesis is the final process that completes cell division, during which one cell becomes two daughter cells. Below are the key stages involved in this process. Process and RegulationContractile ring assemblyAt the middle of the cell (the equator), actin and myosin II gather to form a contractile ring. This ring marks the site where the cell will divide.Cleavage furrow ingressionThe contractile ring constricts, and the cell membrane pinches inward to form a visible furrow. AbscissionAt the thin bridge between the two halves (the intercellular bridge, or midbody), the membranes make the final cut, producing two fully separate daughter cells. If the ring cannot form or tighten properly, or if material remains trapped between the two sides, the split may be delayed or fail. When this happens, cells can stay connected or become multinucleated. Observation Example — Cytokinesis Inhibition With the steps and control conditions above in mind, the example below shows how interfering with the contractile ring alters cell division outcome. Control HeLa cells expressing tdTomato-actin form a clear contractile ring, the cleavage furrow ingresses, and abscission completes division into two daughter cells. Cytochalasin B–treated cells show impaired ring formation and weak constriction, so the furrow stalls and division does not finish. Some cells remain connected or become multinucleated. 👉🏻 For detailed information, see the Application Notes In this article, we explored the processes and regulatory mechanisms of Mitosis and Cytokinesis, demonstrating how live-cell imaging makes it possible to observe these events clearly in real time. The results were obtained using Celloger® Mini Plus and Celloger® Pro, which provide consistent and high-quality imaging data to support research. For more details, please visit our homepage and product page. 🧬 Learn more about Celloger® on our product page. Application examples below show the Celloger® series in live-cell experiments.

2025-11-28